I played tennis with a friend who liked to adjust his underwear right before I served. It happened so frequently that it frustrated me and caused me to double fault.
I now recall that Kafelnikov was one who liked to subtley put his fingers to his crotch (like he needed to adjust his underwear) before the opposite side served. Was there ever any complaints about him doing that ??

This should be in the "Tips" session, but I'll address the real problem. If you think and worry about this stuff during a match, you are susceptible to being "gamed." Don't be his sucker, fughedaboutit, and just play. Good luck.

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"In theory, there is no difference between practice and theory. In practice, there is." Lawrence Berra